Automatically releasing shackle



Nov. 6, 1956 l. w. HUMPHREY AUTOMATICALLY RELEASING SHACKLE Filed June 22. 1954 INVENTOR. .Z h/Jfump/rrey BY w/f7 p United States Patent 2,769,654 AUTOMATICALLY RELEASING SHACKLE Irl W. Humphrey, Terre Haute, Ind. Application June 22, 1954, Serial No. 438,477 1 Claim. (Cl. 29483) This invention relates shackle; and it consists of a shackle or coupling adapted to be connected between the clevis of .a hand hoist or the like and a weight to be lifted by the hoist; said shackle comprising in combination a shackle bar or link pivoted by a horizontal pivot at substantially its central point to the clevis of a hoisting element and in such manner that the bar is free to pivot in a vertical plane, a load-carrying hook at one end of said bar having a slotted opening which points diagonally upwards when the hook is in its lower or working position and diagonally downwardly when the bar is rotated about its pivot point through an angle of about 90 or more, thereby causing release of any load carried by said hook, a fastening element mounted on the end of the bar opposite the hook having a weight suflicient to counterbalance the weight of the hook and thereby to cause the bar to. pivot into load releasing position whenever tension on the hook caused bythe load is relaxed; said fasteningelement :bein-g advantageously attached to the link at a point which is offset from the line joining the weight-carrying point of the hook with the horizontal pivot of the bar; all as more fully hereinafter set forth and as claimed. H

Many automatic releasing shackles have been proposed heretofore. Most of these shackles have been of complicated structure and expensive to manufacture. Most of them are also rather heavy due to their complicated design. I have discovered what I believe to be a novel shackle which requires a minimum of material, which is simple in design and inexpensive to manufacture. In addition my shackle comprises an auxiliary fastening element which can be used to carry light loads in addition to that carried by the shackle proper or, when attached to a line, can be used to release the load at any point or to rotate the beam of the hoist in connection with which the shackle is employed.

Hand hoists used in building construction are generally provided with a main horizontal beam which is pivoted so it can be rotated. A block and tackle, usually of the whip and runner type, is mounted on the beam and the block of the movable pulley is attached to the weight to be lifted. A pulley is usually mounted at each end of the horizontal beam and the hoisting line passe-s over the pulley at the end opposite that which supports the movable pulley. When the weight is lifted to the top of a scaffold, for example, the hoisting line can be pulled in such direction that the weight swings over the scaffold. The line is then played out until the weight rests on the scafiold. If the hoisting block is attached to the weight by the automatically releasing shackle of the present invention, as soon as the weight rests fully on the scaifold thereby releasing the tension on the hoisting block the shackle operates automatically to release the weight from the shackle. When a hoist is thus equipped it is possible for a single operator standing on the ground to hoist weights up and place them on a scalfold without the assistance of an operator on the scaifold.

My shackle is usually attached to a clevis on the to automatically releasing "ice hoisting block of a hoist by means of a bolt which passes through a midpoint of a shackle bar in. such manner that the shackle bar can pivot in a vertical plane about the bolt. One end of the shackle bar can be formed into a hoisting hook which is adapted to be hooked to a line attached to the load or a separate hoisting hook can be secured to the end of the bar in any suitable manner. The opposite end of the shackle bar must be weighted in such fashion that its weight counterbalances the weight ofthe hook thus tending to swing the hook upwardly. In its lowest position the hook is provided with an opening to receive the line attached to the load. This opening points diagonally upwardly and the hook is held in this position by the tension of the load. But as soon as the tension of the load is released, for example, when the load comes to rest on the scalfold, the weight at the opposite end of the shackle bar operates to rotate the bar about its pivot point into its load-releasing position.

The hook,and the weight at the opposite end of the shackle bar must be so constructed and arranged that the shackle bar is rotated by the weight so that the opening of the hook turns either directly or at least diagonally downwards so that the line attached to theweight drops ofi the hook thereby separating the shackle from the weight. The hoisting block with its attached shackle can then be lowered to the ground to be attached to another-load tobe lifted. The weight at the end'of the shackle bar must be attached in such manner that it is effective to :pivot the shackle bar even when the latter is in its vertical load-carrying position. This means that v the effective center of gravity. of the weight must be offset from the line connecting the point of attachment of the load with the. pivot; of the shackle bar. The weight and the hook opening must be positioned on the same side of the longitudinal axis of the shackle bar.

7 I have found, that the most convenient weight tobe attachedlto the shackle bar to counterbalance the weight of its hook isa snap hook or other fastening element to which a cord can be attached. It the line attached to the weight fails to clear the hook of the shackle bar for any reason when the load comes to rest on the scaffold, the hook of the shackle bar can be jerked upwardly by pulling the cord. It is also possible to utilize the snap hook to carry auxiliary loads or with the aid of an attached cord to swing the horizontal hoisting beam about its pivot point.

My invention can be explained in greater detail by reference to the accompanying drawing which shows, more or less diagrammatically a preferred embodiment of my invention. In this showing,

Fig. 1 is a perspective view of my automatically releasing shackle attached to the clevis of a hoisting block,

Fig. 2 is a side elevation of the shackle with its hook swung substantially into its uppermost position, while Fig. 3 is a similar view of the shackle in its load carryin-g position.

In the various figures like parts are designated by the same reference numerals. The hoisting block of a hoist is shown generally at 1 while my shackle is shown generally at 2. The block is suspended by the hoist line 10. As seen from the various figures the shackle has a bar or link 3 which is pivoted at substantially its center point by means of bolt 4 which passes between the depending tongues 5 (Fig. l) of clevis 6 at the bottom of the hoisting block. The shackle bar is formed into the shape of a hook 7 at one end while a snap hook or clip shown generally at 8 is pivoted by means of its link 9 to the opposite end of the bar. The hook end of the bar is lighter in weight than the opposite end of the bar even without the snap hook attached; hence the bar rotates readily about its pivot point into its load releasing position as soon as the tension of any load 12 on the hook is relaxed. If necessary to release the load a cord can be attached to the snap hook and pulled in order to force the shackle bar to rotate into its load releasing position, If this cord is jerked it is possibleto disengage the line 11 attached to the load even if there is a tendency for this line to cling to the hook.

It will be noted that the opening of the hook and the weight represented by the snap hook are both on the same side of the longitudinal axis of the shackle bar; also that the point of attachment of the snap hook is offset from the line joining the point of attachment of the load with the pivot point of the shack-1e bar. This construction is essential in order that the shackle be automatically releasing. The link 9 of the snap hook in the construction shown is larger than the space between the depending arms of the clevis. This stops the shackle bar from rotating counterclockwise beyond its substantially vertical or load carrying position, although this is not essential to the operation of the device.

While I have described what I consider to be the most advantageous embodiments of my automatically releasing shackle it is evident, of course, that various modifications can be made in the specific constructions claimed without departing from the purview of this invention. Thus while I have shown a shackle bar constructed from a steel plate and hence having a rectangular cross section, it is evident thatthis bar can be constructed from stock having cross sections of other shapes. The weighting element 8 can be made integrally with the shackle bar if desired. And of course the hook 7 can be made either integrally with the shackle bar as shown or it may be a separate element attached to the bar in any convenient manner. The pivot bolt can also be' made integrally with the shackle bar, if desired. One advantage of my shackle is the small amount of metal used in the shackle bar and the hook. This saves in thecost of material and since the shackle bar can be made either by stamping, casting or forging operations it can be made very cheaply. It can be attached to any hoisting block simply by passing the conventional bolt of its clevis through the central hole provided in the shackle bar. f

course other means for securing the shackle bar to the hoisting block can be employed. Further modifications which fall Within the scope of the following claim will be immediately evident to those skilled in the art.

What I claim is:

In combination with a hoisting block provided with the usual open clevis having a pair of spaced depending arms, a shackle bar of substantially rectangular shape and of rectangular cross section throughout its length, a bolt adapted pivotally to attach said shackle bar between the depending arms of said clevis, said bolt passing through a hole bored substantially centrally in said shackle bar and through holes provided in the lower ends of the depending arms of said clevis, a diagonal open slot forming a hook located at one end of said shackle bar, said slot having an opening pointing upwardly when the shackle bar is in its load-carrying position and downwardly when the shackle bar is in its load-releasing position, a snap hook pivotally mounted at the opposite end of said shackle bar with its pivot point ofiF-set from the central axis of the shackle bar so that the weight of the snap hook is attached on the same side of said central axis as the slot opening and so the weight of the snap hook tends to rotate the shackle bar to its load-releasing position, said snap hook being attached to the shackle bar by a link which is larger than the space between the depending arms of the clevis so that the shackle bar cannot be rotated beyond its load-carrying position in one direction.

References Cited in the file of this patent UNITED STATES PATENTS 741,014 Covert Oct. 13, 1903 958,978 Spencer May 24, 1910 990,916 Smith May 2, 1911 992,746 Ashdown May 23, 1911 1,162,580 De Mars Nov. 30, 1915 1,188,312 Petrik June 20, 1916 1,344,187 Oliver June 22, 1920 2,666,664 Johnson Jan. 19, 1954 

